Tomato Juice Keeps Emphysema from Developing in Mice

Researchers at Juntendo University School of Medicine first compared the reaction of two mostly similar mouse strains to inhaled cigarette smoke. Since the lungs of one of the mouse strains "naturally" age very quickly, the researchers believed that exposure to inhaled cigarette smoke would induce emphysema in that strain much more quickly than in the other strain. And indeed, they found that after eight weeks of breathing 1.5% tobacco smoke through the nose for 30 minutes a day, five days a week, the test strain, called SAMP1, did develop emphysema, while the control strain, called SAMR1, did not.

Then, using the same experimental method, but substituting a 50% tomato juice mixture for their regular water supply, the researchers again compared the effect of smoking on the mice. They found that "smoke-induced emphysema was completely prevented by concomitant ingestion of the antioxidant lycopene given as tomato juice" in SAMP1 mice. They added: "Smoke exposure increased apoptosis and active caspase-3 of airway and alveolar septal cells and reduced vascular endothelial growth factor (VEGF) in lung tissues, but tomato juice ingestion significantly reduced apoptosis and increased tissue VEGF level."

The tomato-lycopene link is made even more interesting because late last year the U.S. Food and Drug Administration gave permission for some tomato products to carry highly-qualified labelling claims linking men's eating tomato products with a reduced incidence of prostate cancer. In reaching its decision, the FDA noted that it's unclear whether lycopene alone is responsible for the tomato products' effect.

Similarly, the Japanese researchers noted: "Since mice were given tomato juice instead of pure lycopene preparation, we can not exclude the possibility that other ingredients contained in tomato juice affected the results…." However, they cautioned: "We can't simply accept that these results go beyond the mouse model. They are not so smoothly applied to human beings."

Therefore, the next steps would be to test how tomato juice ingestion might affect human patients with chronic obstructive lung disease (COPD).